Japan's struggling space programme suffered a setback today, when its biggest rocket to date gracefully blasted off the launch pad but lost half its payload.

Japan's struggling space programme suffered a setback today, when its biggest rocket to date gracefully blasted off the launch pad but lost half its payload.

Hours after the black and orange H-2A rocket peeled into a pale blue sky on a billowing column of white smoke, mission controllers were still trying to figure out whether one of two probes had been put in orbit.

The rocket itself fired almost perfectly and successfully deployed the second satellite.

But the initial payload glitch, affecting a research module, was another blot on Japan's bid to compete with the US and Europe in the lucrative satellite launching business.

"If you can't get a satellite in orbit it doesn't count," said space analyst Joan Johnson-Freese, of the Asia-Pacific Centre for Security Studies. "It's a blow to the space programme, but not an unrecoverable one."